A submachine gun (SMG) is a shoulder fired automatic firearm and machine gun subtype designed to fire pistol cartridges from a box magazine. It combines the automatic fire of larger MGs with the portability and smaller cartridge of a pistol. They are meant to be lightweight, and portable weapons suited for close range combat where they are easily maneuvered. For their efficiency and ease of use in close quarters, they sacrifice stopping power and accuracy at range.

Once a part of frontline infantry in late World War I, World War II, and the Vietnam War, they have been largely phased out. Modern advances in body armor have rendered the low powered pistol rounds used largely ineffective due to their inability to penetrate. Instead, many submachine guns see use as personal defense weapons (PDWs), often firing armor-piercing rounds, in police and paramilitary forces.

Submachine guns have appeared in every installment in the Battlefield series and have been depicted as fully-automatic weapons, but can be fired in controlled bursts. Generally, submachine guns are balanced to do high damage at close range with a very short damage dropoff point, and most possess high spread with a relatively high rate of spread increase and a high rate of fire. This tends to limit their effectiveness over range.

Before Battlefield 2, the accuracy of submachine guns was limited as it was not possible to look down the weapon's iron sights. Instead, the crosshair would only be zoomed in. This was true of games before Battlefield 2 such as Battlefield 1942 and Battlefield Vietnam. This continued to be true for a few games after Battlefield 2 as well such as Battlefield: Bad Company and Battlefield 1943. This effect was to make it feel more like a short-ranged weapon.